Hydronic heating systems typically include many final heating loops, each of which is adjustable for rate of flow to increase or decrease heat delivered. For optimal performance of pumps and the motors that drive them, it is preferred that each hydronic loop, whether coming directly from the boiler or a sub-loop, not be subjected to a widely varying range of resistance. Consequently, it is common practice to start with a primary loop from the boiler which is driven by a pump, or sometimes convection. The primary loop has low enough resistance to maintain good flow. Tapping off of the primary loop are several secondary loops, each with its own pump that may be turned on and off or varied in speed. Each secondary loop draws hot liquid from a secondary outlet off the primary loop and injects return liquid through a secondary inlet to the primary loop, typically closely spaced and downstream of the secondary outlet to provide good hydraulic separation of the loops. Thus, the pump or convective force which drives the primary loop experiences relatively constant flow resistance whether the pump for any secondary loop is on or off. The inlet and outlet for a secondary loop should be placed on the primary loop no more than 4 pipe diameters, center to center, away from each other to prevent a pressure differential due to friction loss in the primary loop between the inlet and outlet. Such a pressure differential would cause flow to be induced in the secondary loop even if its pump were not running.
Each secondary loop typically flows through the final delivery radiator system. Alternatively, there can be a tertiary loop drawing off a secondary loop where the tertiary loop directs the liquid through the radiator system. In this case, the second loop might be called an “intermediate” loop while the third loop is called a “secondary” loop. When a loop farther from the heat source taps into a loop closer to the heat source, the closer loop may be called a “main” loop and the farther loop may be called “branch” loop, whether the connection is between a first loop and a second loop or between a second loop and a third loop, etc.
Although it is known to combine many components that are used between a boiler and the secondary loops into a mechanical module, there are no modular components for making the connections between the boiler and such a mechanical module or between the mechanical module and the secondary loops that make a complete and flexible system. Preassembling hydronic mechanical modules with many of the normally utilized mechanical parts (for example, but not limited to, pumps, valves, expansion tanks, check valves, etc.) has been attempted in the past, but has been unsatisfactory, since many of the required additional primary, intermediate and secondary components have been required to be field installed, often sweated in place or field fabricated resulting in many errors, poor practice, poor hydronic design, and has been very labor intensive. Thus, a way to facilitate more foolproof and effective practice is needed.
Mechanical modules with integral adaptors or modular transition adaptors for mechanical modules that facilitate the use of primary, secondary, and intermediate component modules in a systematic way would be a significant improvement. Primary, secondary and intermediate component modules that will systematically attach to the transition adaptor will allow for manufactured assembly and easy connection of primary, secondary and intermediate component modules, reducing installation errors, time and often cost.